Compression Blow Forming (CBF) is a process for the manufacture of small to medium sized thin walled containers, such as bottles. The CBF processing of propylene-based polymers is very difficult for two main reasons: such polymers are difficult to cut after extrusion to form a particulate (gob), and such polymers are difficult to stretch and blow mold after compression. Thus, there is a need for compression, blow formed articles formed from propylene-based polymers.
International Publication No. WO 2009/055527 discloses a rubber modified monovinylidene aromatic polymer composition, in the form of a stretch blow molded article. The composition comprises the following: (A) a monovinylidene aromatic polymer a having a weight average molecular weight (Mw) from about 190,000 to about 350,000 g/mol; (B) from about 3.5 to about 10 percent, by weight, based on the weight of components (A), (B) and (C), of a grafted, cross-linked rubber polymer; (C) optionally up to about 5 percent, by weight, based on the weight of components (A), (B) and (C) of a plasticizer; and (D) optional non-polymeric additives and stabilizers.
U.S. Publication No. 2009/0057961 discloses a process for producing clear injection stretch blow molded containers, comprising molding a propylene polymer composition comprising the following: (A) a propylene polymer chosen from: (i) a homopolymer or mini-random copolymer of propylene containing up to 1.0 wt % of at least one of ethylene and C4-C10 α-olefins; (ii) a random copolymer of propylene and at least one olefin chosen from ethylene and C4-C10 α-olefins; and (iii) mixtures thereof; and (B) about 1 to about 1000 ppm, based on the weight of the propylene polymer, of at least one radiant heat absorbent; thereby forming a preform; and II. stretch blow molding the preform; and wherein in step 11, heat is supplied by infrared radiation. The containers have a haze value less than 25.0%.
Additional articles and/or compositions are described in U.S. Pat. No. 7,303,797; and International Publication Nos. WO 2009/067337; WO 2007/117520; WO 2009/085922. As discussed, there is a need for compression, blow formed articles formed from propylene-based polymers.